Intersection Observer & Efficient Scroll Handling

const options = {
  root: null,
  rootMargin: '0px',
  threshold: [0, 0.5, 1.0]
};

const observer = new IntersectionObserver(callback, options);

It defines the scroll speed sensitivity
It sets the update frequency of the observer
It specifies at what percentage of visibility the callback should fire
The threshold option in Intersection Observer specifies at what percentage of the target element's visibility the callback should be triggered. It can be a single number or an array of numbers between 0.0 and 1.0. For example: 0.0 means the callback triggers as soon as even one pixel becomes visible, 1.0 means the entire element must be visible, and 0.5 means the callback triggers when 50% of the element is visible. Multiple thresholds allow for fine-grained control over when the callback fires, making it useful for tracking engagement or implementing progressive loading effects.
It determines the size of the root element